Edge dislocations bowing out from a row of collinear obstacles in Al

Abstract

The bowing of edge dislocations from a row of collinear obstacles in Al is studied using concurrent atomistic-continuum simulations of submicron-sized realizations containing up to 238 million atoms. Results show that (1) as the number of adjacent bowed-out dislocation segments increases, the critical dislocation depinning stress approaches that for an infinite array of obstacles and (2) for the unstable overall semi-elliptic dislocation configuration, the presence of intermediate obstacles reduces the dislocation half-loop height, but doesn't affect the critical shear stress. Our work highlights the significance of the effects of adjacent bowed-out segments on cooperative dislocation bow-out.